/*
  * SubRip subtitle muxer
  * Copyright (c) 2012  Nicolas George <nicolas.george@normalesup.org>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include "avformat.h"
 #include "internal.h"
 #include "libavutil/log.h"

 #include "libavutil/intreadwrite.h"

 
 /* TODO: add options for:
    - character encoding;
    - LF / CRLF;
    - byte order mark.
  */
 
 typedef struct SRTContext{
     unsigned index;
 } SRTContext;
 
 static int srt_write_header(AVFormatContext *avf)
 {

     SRTContext *srt = avf->priv_data;
 

     if (avf->nb_streams != 1 ||
         avf->streams[0]->codec->codec_type != AVMEDIA_TYPE_SUBTITLE) {
         av_log(avf, AV_LOG_ERROR,
                "SRT supports only a single subtitles stream.\n");
         return AVERROR(EINVAL);
     }

     if (avf->streams[0]->codec->codec_id != AV_CODEC_ID_TEXT &&

         avf->streams[0]->codec->codec_id != AV_CODEC_ID_SUBRIP &&

         avf->streams[0]->codec->codec_id != AV_CODEC_ID_SRT) {

         av_log(avf, AV_LOG_ERROR,
                "Unsupported subtitles codec: %s\n",
                avcodec_get_name(avf->streams[0]->codec->codec_id));
         return AVERROR(EINVAL);
     }
     avpriv_set_pts_info(avf->streams[0], 64, 1, 1000);

     srt->index = 1;

     return 0;
 }
 
 static int srt_write_packet(AVFormatContext *avf, AVPacket *pkt)
 {
     SRTContext *srt = avf->priv_data;

     int write_ts = avf->streams[0]->codec->codec_id != AV_CODEC_ID_SRT;

 
     if (write_ts) {
         int64_t s = pkt->pts, e, d = pkt->duration;

         int size, x1 = -1, y1 = -1, x2 = -1, y2 = -1;
         const uint8_t *p;
 
         p = av_packet_get_side_data(pkt, AV_PKT_DATA_SUBTITLE_POSITION, &size);
         if (p && size == 16) {
             x1 = AV_RL32(p     );
             y1 = AV_RL32(p +  4);
             x2 = AV_RL32(p +  8);
             y2 = AV_RL32(p + 12);
         }

 
         if (d <= 0)

             /* For backward compatibility, fallback to convergence_duration. */

             d = pkt->convergence_duration;

         if (s == AV_NOPTS_VALUE || d < 0) {

             av_log(avf, AV_LOG_WARNING,
                    "Insufficient timestamps in event number %d.\n", srt->index);
             return 0;

         }
         e = s + d;

         avio_printf(avf->pb, "%d\n%02d:%02d:%02d,%03d --> %02d:%02d:%02d,%03d",

                        srt->index,
                        (int)(s / 3600000),      (int)(s / 60000) % 60,
                        (int)(s /    1000) % 60, (int)(s %  1000),
                        (int)(e / 3600000),      (int)(e / 60000) % 60,
                        (int)(e /    1000) % 60, (int)(e %  1000));

         if (p)
             avio_printf(avf->pb, "  X1:%03d X2:%03d Y1:%03d Y2:%03d",
                         x1, x2, y1, y2);
         avio_printf(avf->pb, "\n");

     }
     avio_write(avf->pb, pkt->data, pkt->size);
     if (write_ts)
         avio_write(avf->pb, "\n\n", 2);

     srt->index++;

     return 0;
 }
 
 AVOutputFormat ff_srt_muxer = {
     .name           = "srt",

     .long_name      = NULL_IF_CONFIG_SMALL("SubRip subtitle"),

     .mime_type      = "application/x-subrip",
     .extensions     = "srt",
     .priv_data_size = sizeof(SRTContext),
     .write_header   = srt_write_header,
     .write_packet   = srt_write_packet,

     .flags          = AVFMT_VARIABLE_FPS | AVFMT_TS_NONSTRICT,

     .subtitle_codec = AV_CODEC_ID_SUBRIP,

 };